Table 2. Multilevel logistic regression models for individual and household/community predictors of maternal age at first birth.
| Variables | Model 0 | Model I | Model II | Model III |
|---|---|---|---|---|
| aOR [95% CI] | aOR [95% CI] | aOR [95% CI] | ||
| Fixed effects results | ||||
| Individual-level variables | ||||
| Educational level | ||||
| No Education | RC | RC | ||
| Primary | 0.93[0.85–1.00] | 1.01[0.92–1.09] | ||
| Secondary & above | 0.37***[0.34–0.40] | 0.46***[0.42–0.50] | ||
| Currently working | ||||
| Not working | RC | RC | ||
| Working | 0.97[0.91–1.03] | 0.97[0.91–1.03] | ||
| Marital status | ||||
| Unmarried | RC | RC | ||
| Married | 0.81*** [0.74–0.88] | 0.78***[0.71–0.85] | ||
| Religion | ||||
| Christianity | RC | RC | ||
| Islam | 1.28***[1.17–1.40] | 1.17**[1.05–1.29] | ||
| Traditionalist & others | 1.37*[1.03–1.81] | 1.39*[1.05–1.84] | ||
| Ethnicity | ||||
| Hausa | RC | RC | ||
| Yoruba | 0.31***[0.27–0.35] | 0.46***[0.39–0.56] | ||
| Igbo | 0.36***[0.31–0.41] | 0.44***[0.35–0.55] | ||
| Others | 0.72***[0.66–0.79] | 0.78***[0.71–0.86] | ||
| Media exposure | ||||
| No | RC | RC | ||
| Yes | 0.88***[0.83–0.94] | 0.97 [0.91–1.04] | ||
| Household/community level variables | ||||
| Place of residence | ||||
| Urban | RC | RC | ||
| Rural | 1.02[0.93–1.12] | 1.05[0.96–1.15] | ||
| Region | ||||
| North Central | RC | RC | ||
| North East | 1.61***[1.44–1.81] | 1.26***[1.13–1.42] | ||
| North West | 1.82***[1.63–2.03] | 1.24**[1.09–1.40] | ||
| South East | 0.56***[0.49–0.65] | 1.06[0.83–1.35] | ||
| South South | 1.01[0.89–1.15] | 1.11[0.97–1.27] | ||
| South West | 0.62***[0.54–0.71] | 0.92[0.78–1.09] | ||
| Wealth index | ||||
| Poorest | RC | RC | ||
| Poorer | 0.96[0.88–1.05] | 1.00[0.92–1.09] | ||
| Middle | 0.88**[0.79–0.97] | 0.98[0.89–1.08] | ||
| Richer | 0.77***[0.68–0.86] | 0.96 [0.85–1.08] | ||
| Richest | 0.41***[0.36–0.48] | 0.61***[0.53–0.71] | ||
| Sex of household head | ||||
| Male | RC | RC | ||
| Female | 0.95[0.88–1.03] | 0.89*[0.81–0.98] | ||
| Community literacy level | ||||
| Low | RC | RC | ||
| Medium | 0.73***[0.66–0.81] | 0.90*[0.82–0.99] | ||
| High | 0.46***[0.40–0.52] | 0.71***[0.62–0.81] | ||
| Community socioeconomic status | ||||
| Low | RC | RC | ||
| Medium | 1.05[0.93–1.18] | 0.99 [0.88–1.12] | ||
| High | 0.98[0.87–1.11] | 0.89 [0.79–1.01] | ||
| Random effects results | ||||
| PSU Variance (95% CI) | 0.93[0.84–1.04] | 0.18[0.14–0.21] | 0.17[0.14–0.21] | 0.14[0.11–0.17] |
| ICC | 0.22 | 0.05 | 0.04 | 0.04 |
| LR Test | χ2 = 32854.90, p<0.001 | χ2 = 248.49, p<0.001 | χ2 = 258.32, p<0.001 | χ2 = 169.99, p<0.001 |
| Wald χ2 | Reference | 2464.16*** | 2090.38*** | 2781.62*** |
| Model fitness | ||||
| Log-likelihood | -18338.06 | -17385.71 | -17592.73 | -17253.03 |
| AIC | 36680.11 | 34795.42 | 35219.45 | 34560.05 |
| BIC | 36696.73 | 34895.13 | 35360.70 | 34784.39 |
| Number of clusters | 1389 | 1389 | 1389 | 1389 |
Weighted NDHS, 2018
Exponentiated coefficients; 95% confidence intervals in brackets; AOR = adjusted Odds Ratios; CI = Confidence Interval; RC = Reference Category.
*p< 0.05
**p< 0.01
***p< 0.001.
AIC = Akaike’s Information Criterion; BIC = Schwarz’s Bayesian Information Criteria; PSU = Primary Sampling Unit; ICC = Intra-Class Correlation; LR Test = Likelihood ratio Test.
Model 0 is the null model, a baseline model without any determinant variable.
Model I is adjusted for individual-level variables (Educational level, currently working, marital status, religion, ethnicity and media exposure).
Model II is adjusted for household/community level variables (Place of residence, region, wealth index and sex of household head).
Model III is the final model adjusted for individual and household/community level variables